WO2023140071A1

WO2023140071A1 - Motor stator and motor provided with same

Info

Publication number: WO2023140071A1
Application number: PCT/JP2022/048153
Authority: WO
Inventors: 直嗣北山; 隼人小林
Original assignee: Ntn株式会社
Priority date: 2022-01-20
Filing date: 2022-12-27
Publication date: 2023-07-27
Also published as: JP2023106031A

Abstract

The present invention involves sequentially winding one continuous coil wire CL around each of a total of 12 teeth 4 by concentrated winding to form four U-phase coils, four V-phase coils, and four W-phase coils in the stated order along the length direction of the coil wire CL. Crossover wire portions CL₂, CL₆, and CL₁₀ of the coil wire CL for connecting in parallel the coils of the same phase to each other are connected to a connection terminal 5a of a U-phase bus bar 5, a connection terminal 6a of a V-phase bus bar 6, and a connection terminal 7a of a W-phase bus bar 7, respectively, and crossover wire portions CL₄, CL₈, and CL₁₂ of the coil wire CL for connecting the coils of different phases to each other are connected to connection terminals 8a, 8b, and 8c of a neutral point bus bar 8, respectively, to form a star-connected motor drive circuit 20.

Description

Motor stator and motor provided with the same

The present invention relates to a motor stator and a motor including the same, and more particularly to a three-phase brushless motor stator that can be suitably used as a drive source for electrical equipment mounted on a vehicle (automobile) such as an electric oil pump and an electric parking brake.

For example, Patent Document 1 below discloses an inner-rotor type three-phase brushless motor (hereinafter simply referred to as "motor") having a motor stator in which a coil (a U-phase coil, a V-phase coil, or a W-phase coil) is wound on each of a plurality of teeth provided at intervals in the circumferential direction on a cylindrical stator core via an insulating member also called an insulator, and a motor rotor disposed radially inward of the motor stator. In this motor, the motor stator further includes a busbar unit arranged axially outside the stator core. The busbar unit includes a plurality of busbars (a U-phase busbar, a V-phase busbar, a W-phase busbar, a neutral point busbar, etc.) made of a conductive material such as copper, and a busbar holder made of an insulating material such as resin and holding the plurality of busbars in a non-contact state. A coil wire connection terminal is provided on each phase bus bar, and a motor drive circuit (power supply circuit) is formed by connecting the end portion of each coil drawn out to the axially outer side of the stator core to the corresponding bus bar connection terminal.

By the way, brushless motors can be broadly classified into "integer groove motors" in which the "number of slots per pole and phase q" is a positive integer, and "fractional groove motors" in which the "number of slots per pole and phase q" is a fraction (not a positive integer). “The number of slots q per pole per phase” is calculated by the formula q=N/(m×P), where N is the number of grooves (slots) formed between adjacent teeth in the circumferential direction, m is the number of phases of the motor, and P is the number of poles (number of permanent magnets) of the motor. Therefore, for example, a 10-pole 12-slot three-phase brushless motor (N=12, m=3, P=10) is a "fractional groove motor" because q=12/(3·10)=2/5.

Whether the brushless motor is an integer groove motor or a fractional groove motor is appropriately selected according to the required characteristics, but if the number of slots is the same, the fractional groove motor can make the cogging torque smaller than the integer groove motor, so it is said that it is easy to realize a quiet and high output efficiency motor.

International publication WO2020/013078

In recent years, the electrification of automobiles has progressed rapidly, and the demand for motors for various electrical equipment installed in automobiles tends to increase. In order to reduce the cost of the motor, it is desirable to reduce the number of coil connection locations as much as possible when forming the drive circuit. V phase: 2 points each, N phase (neutral point): 6 points, totaling 12 points. As described above, if there are 12 coil connection points, it becomes difficult to reduce the cost of the motor stator and, in turn, the motor.

In view of the above circumstances, the main object of the present invention is to enable the low-cost formation of a drive circuit for a motor (three-phase brushless motor) formed by interconnecting a plurality of U-phase coils, V-phase coils and W-phase coils, thereby reducing the cost of a motor stator having the drive circuit.

The present invention, which has been devised to achieve the above objects,
A motor stator comprising a cylindrical stator core having a plurality of teeth spaced apart in a circumferential direction, and a plurality of U-phase coils, V-phase coils, and W-phase coils formed by winding coil wires around each of the plurality of teeth via an insulating member,
A plurality of U-phase coils, a plurality of V-phase coils, and a plurality of W-phase coils are sequentially formed along the longitudinal direction of the coil wire by sequentially winding one continuous coil wire around each of the plurality of teeth by concentrated winding,
Of the coil wire, the crossover wire portion connecting the U-phase coils in parallel, the crossover wire portion connecting the V-phase coils in parallel, and the crossover wire portion connecting the W-phase coils in parallel are respectively connected to the connection terminal of the U-phase bus bar, the connection terminal of the V-phase busbar, and the connection terminal of the W-phase busbar. A star-connected motor drive circuit is formed by connecting the connecting wire portion to the connection terminal of the neutral point bus bar.

The above configuration can be applied, for example, to a stator for a 12-slot three-phase brushless motor described above, specifically, a stator for a 12-slot three-phase brushless motor having four U-phase coils connected in two parallel and two series, four V-phase coils connected in two parallel and two series, and four W-phase coils connected in two parallel and two series, which are star-connected. In this case, the number of U-phase to W-phase coils can be reduced to 1 each, and the number of neutral points can be reduced to 3, totaling 6 (reduced by half from the maximum of 12). As a result, the cost of the motor stator can be reduced through the simplification of the connection work.

In the above configuration, a total of four bus bars, each having a coil wire connection terminal, can be held in a non-contact state with the insulating member on one axial end side of the stator core. This means that the insulating member for insulating between the teeth and the coil wound thereon integrally has a portion corresponding to the busbar holder of the conventional busbar unit. In this case, the number of parts can be reduced as compared with the conventional product. Further, in this case, when the coil is wound, the planned connection point of the coil wire to the busbar can be reliably brought into contact with the connection terminal of the busbar, so that the connection work performed after the coil winding can be easily and accurately performed. Therefore, it is possible to reduce the cost by reducing the number of parts and to reduce the cost by facilitating the connection work.

The U-phase to W-phase busbars and the neutral point busbar can be held by the insulating member by, for example, outserting (fitting) into grooves provided in the insulating member. With this configuration, the connecting wire portion of the coil wire can be connected to the connection terminal of the bus bar that is relatively movable with respect to the insulating member. Therefore, even if the formation position of the connecting wire portion is deviated from the predetermined position, the connection work can be performed with high accuracy. In this case, when the crossover portion is connected to the connection terminal, the relative movement of the busbar with respect to the insulating member can be restricted (the busbar is fixedly held with respect to the insulating member), so that the busbar can be prevented from being separated from the insulating member when handling the motor stator.

Each crossover portion can be connected to a corresponding connection terminal by, for example, fusing, which is also referred to as thermal crimping. In the case of fusing, the wire can be connected to the terminal almost at the same time as the insulating film of the coil wire made of the wire with the insulating film is removed, so the wire connection work can be performed efficiently and accurately.

In the above configuration, the winding directions in the circumferential direction of each connecting wire portion can all be the same. Although it is possible to fold the connecting wire portion, in this case, there is a concern that the motor stator becomes longer in the axial direction due to the overlapping of the connecting wire portions in the axial direction. Therefore, if all the connecting wire portions are wound in the same direction in the circumferential direction, it is advantageous to make the motor stator, and thus the motor, compact in the axial direction.

The present invention can be applied to a motor stator in which the parallel number of U-phase coils in the U-phase coil section, the parallel number of V-phase coils in the V-phase coil section, and the parallel number of W-phase coils in the W-phase coil section are all even numbers (same and even numbers).

Since the motor stator according to the present invention has the above features, the motor (three-phase brushless motor) including the motor stator according to the present invention and the motor rotor can be provided at low cost.

As described above, according to the present invention, a motor (three-phase brushless motor) drive circuit formed by star-connecting a plurality of U-phase coils, V-phase coils, and W-phase coils can be formed at low cost. As a result, it is possible to reduce the cost of the stator for the motor having the drive circuit, and thus the cost of the motor.

1 is a schematic perspective view of a motor stator according to an embodiment of the present invention before coil winding; FIG. FIG. 2 is a view of a bus bar separated from the motor stator of FIG. 1; 1 is a schematic plan view of a motor stator according to an embodiment of the invention; FIG. 4 is a diagram for explaining a winding structure of a coil in the motor stator of FIG. 3; FIG. 5 is a diagram showing a star-connected motor drive circuit obtained by the winding structure of FIG. 4; FIG. 5 is a diagram showing a star-connected motor drive circuit obtained when a winding structure different from the coil winding structure of FIG. 4 is adopted; FIG. 1 is a longitudinal sectional view conceptually showing one configuration example of a motor provided with a motor stator according to an embodiment of the present invention; FIG.

Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 7). In the following description, the terms "axial direction," "radial direction," and "circumferential direction" are used to indicate directionality, and these are respectively the direction parallel to the axis of the motor stator 1, the radial direction of a circle centered on the axis, and the circumferential direction of a circle centered on the axis.

First, based on FIG. 7, a configuration example of a motor 30 having a motor stator 1 according to an embodiment of the present invention will be briefly described. A motor 30 shown in FIG. 7 includes a motor stator 1, a motor rotor 32 disposed radially inside the motor stator 1 with a radial gap (not shown) therebetween, and a casing 31 housing them. The illustrated motor rotor 32 includes an output shaft 33, a rotor core 34 provided to be rotatable integrally with the output shaft 33, and a plurality of (e.g., 10 poles) permanent magnets 35 held by the rotor core 34 at regular intervals in the circumferential direction.

The motor 30 shown in FIG. 7 can be used, for example, as a drive source for an electric pump mounted on a vehicle, more specifically, an electric pump (electric oil pump) that is attached to the transmission case of the vehicle and used to ensure the oil pressure required inside the transmission by pumping oil to the transmission while the engine is stopped. Although not shown, when the motor 30 is used as a drive source for an electric oil pump, a pump rotor that can rotate integrally with the output shaft 33 is provided at the free end of the output shaft 33 outside the casing 31 .

Next, a motor stator 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic perspective view of a motor stator 1 (an assembly in which an insulating member and a bus bar are assembled to a stator core, which is a constituent member of the motor stator 1) before coil winding, FIG. 2 is a view of the motor stator 1 in FIG. 1 with the bus bar separated, and FIG.

The motor stator 1 includes a cylindrical stator core 2 made of a metal material (for example, an electromagnetic steel sheet) with excellent magnetic properties, a U-phase busbar 5, a V-phase busbar 6, a W-phase busbar 7 and a neutral point busbar (N-phase busbar) 8, an insulating member 10 made of an insulating material such as a resin material, and a plurality of coils C.

The stator core 2 has a tubular portion 3 and teeth 4 protruding from the inner peripheral surface of the tubular portion 3 toward the center of the stator core 2 and around which a coil C (see FIG. 3) is wound via an insulating member 10. In this embodiment, a total of 12 teeth 4 are provided at regular intervals in the circumferential direction. In the following description, the twelve teeth 4 arranged in order along the circumferential direction of the stator core 2 are referred to as the first teeth 4A to the twelfth teeth 4L (see FIG. 3). In the motor stator 1 shown in FIG. 3, the first tooth 4A is arranged at the 12 o'clock position of the stator core 2, and thereafter, the remaining 11 teeth 4 (the second tooth 4B to the 12th tooth 4L) are arranged in order at a pitch of 30° counterclockwise.

As described above, the motor stator 1 of this embodiment has a total of 12 teeth 4 (slots formed between the teeth 4), and the motor rotor 32 arranged radially inward of the motor stator 1 is provided with a ten-pole permanent magnet 35 (see FIG. 7). Therefore, the motor stator 1 of this embodiment is a motor stator for a three-phase brushless motor with 10 poles and 12 slots. Such a brushless motor is a so-called fractional groove motor in which "the number of slots per pole per phase q" calculated by the formula q=N/(m×P) is a fraction (=2/5), where N is the number of slots, m is the number of phases of the motor, and P is the number of permanent magnets (number of poles) provided in the motor rotor.

The insulating member 10 includes a first covering portion 11 that covers the inner peripheral surface of the cylindrical portion 3 of the stator core 2, a second covering portion 12 that covers the teeth 4 of the stator core 2 (more specifically, portions of the teeth 4 on which the coils 20 are wound), and a holding portion 13 that is provided at one axial end of the stator core 2 and holds the bus bars 5 to 8 in a non-contact state.

The bus bars 5 to 8 are members that supply (distribute) the motor driving current output from an external power source (not shown) to the coil C. Therefore, the busbars 5 to 8 are all made of a highly conductive metal material such as copper or aluminum alloy.

The U-phase bus bar 5, V-phase bus bar 6, and W-phase bus bar 7 of the present embodiment each have one

connection terminal

5a, 6a, 7a to which the coil wire CL is connected, and one

power supply terminal

5b, 6b, 7b to be connected to an external power supply (see FIG. 2). These U-phase bus bar 5, V-phase bus bar 6, and W-phase bus bar 7 are held by a holding portion 13 with

terminals

5a, 5b, 6a, 6b, 7a, and 7b exposed to the outside, as shown in FIG. Further, the neutral point bus bar 8 has

connection terminals

8a, 8b, and 8c that form neutral points respectively with a U-phase coil portion 21, a V-phase coil portion 22, and a W-phase coil portion 23, which will be described later (see FIG. 2). As shown in FIG. 1, the neutral point bus bar 8 is also held by the holding portion 13 with the

terminals

8a, 8b, and 8c exposed to the outside.

As shown in FIG. 3, the coil C is wound around each of a total of 12 teeth 4 via (the second covering portion 12 of) the insulating member 10 attached to the stator core 2 . The coil C includes a total of four U-phase coils CU1 to CU4, a total of four V-phase coils CV1 to CV4, and a total of four W-phase coils CW1 to CW4, and these are star-connected using the bus bars 5 to 8 to form a motor drive circuit (power supply circuit) 20 as shown in FIGS.

A total of 12 coils C are formed by sequentially winding a single continuous coil wire (a conductive wire made of a metal material such as copper coated with an insulating film) CL around each of a total of 12 teeth 4 covered with (the second covering portion 12 of) an insulating member 10 by concentrated winding. In this embodiment, as shown in FIGS. 4 and 5, the U-phase coil CU1 is first formed (wound), and thereafter, the coils C are formed in the order of CU2→CU3→CU4→CV3→CV4→CV1→CV2→CW1→CW2→CW3→CW4. A coil winding process for winding the coil C around each tooth 4 and a wire connection process performed after the coil winding process will be described below.

[Coil winding process]
As shown in FIG. 4, in this step, first, the coil wire CL is wound around the outer periphery of the first tooth 4A counterclockwise a predetermined number of times. As a result, the U-phase coil CU1 is wound around the outer periphery of the first tooth 4A by concentrated winding. The winding of the coil wire CL around the outer periphery of the first tooth 4A is started from one axial end side of the stator core 2 (the side where the holding portion 13 is provided, which is the upper side of the paper surface in FIG. 4; the same applies to the following description), and ends at the one axial end side of the stator core 2. That is, when the U-phase coil CU1 is wound around the first teeth 4A, both the winding start portion and the winding end portion of the coil wire CL are pulled out to one end side of the stator core 2 in the axial direction. The same applies when the remaining U-phase coils CU2-CU4, V-phase coils CV1-CV4, and W-phase coils CW1-CW4 are wound around the corresponding teeth. This is because the portions (crossover portions CL ₁ to CL ₁₂ ) of the coil wire CL that are interposed between and connect two coils adjacent in the longitudinal direction are arranged on one end side in the axial direction of the stator core 2, and are connected to the connection terminals of the bus bars 5 to 8 held by the holding portion 13.

After winding the U-phase coil CU1, the coil wire CL is wound a predetermined number of times in the clockwise direction from one axial end side of the stator core 2 around the outer periphery of the second tooth 4B. As a result, the U-phase coil CU2 is wound around the outer periphery of the second tooth 4B by concentrated winding.

After winding the U-phase coil CU2, the coil wire CL is wound a predetermined number of times in the counterclockwise direction from one axial end of the stator core 2 to the outer periphery of the seventh tooth 4G. As a result, the U-phase coil CU3 is wound around the outer periphery of the seventh tooth 4G by concentrated winding. Before the coil wire CL is wound around the outer periphery of the seventh tooth 4G, (a part of) the connecting wire portion CL ₂ of the coil wire CL interposed between the U-phase coils CU2 and CU3 to connect the two coils is wound around the connection terminal 5a of the U-phase bus bar 5 held by the holding portion 13. After winding the U-phase coil CU3, the coil wire CL is wound a predetermined number of times in the clockwise direction from one axial end side of the stator core 2 around the outer periphery of the eighth tooth 4H. As a result, the U-phase coil CU4 is wound around the outer periphery of the eighth tooth 4H by concentrated winding.

Here, in the implementation stage of the coil winding process, the busbars 5 to 8 may be held by the holding portion 13 so as not to be relatively movable with respect to the insulating member 10, or may be held by the holding portion 13 so as to be relatively movable with respect to the insulating member 10. The former configuration can be obtained, for example, by injection-molding the insulating member 10 (holding portion 13) with resin using the busbars 5 to 8 as insert parts. The latter configuration can be obtained by injection-molding an insulating member 10 (holding portion 13) having grooves 13a to 13d for fitting busbars with resin, and then outserting the busbars 5 to 8 into the grooves 13a to 13d, as shown in FIG. With the latter configuration, the work of winding the coil wire (connection wire portion) to the connection terminal of the bus bar performed in the coil winding process can be facilitated as compared with the former configuration. When the latter configuration is adopted, relative movement of the busbars 5 to 8 with respect to the insulating member 10 can be restricted (busbars 5 to 8 fixed to the holding portion 13) by connecting coil wires to the connection terminals of each busbar.

After winding the U-phase coil CU4 (a total of four U-phase coils CU1 to CU4), the coil wire CL is wound from one end of the stator core 2 in the axial direction around the outer circumference of the ninth tooth 4I in the counterclockwise direction for a predetermined number of times. As a result, the V-phase coil CV3 is wound around the outer periphery of the ninth tooth 4I by concentrated winding. Before winding the coil wire CL around the outer circumference of the ninth tooth 4I, (part of) the crossover portion CL ₄ of the coil wire CL connecting the U-phase coil CU4 and the V-phase coil CV3 is wound around the connection terminal 8a of the neutral point bus bar 8 held by the holding portion 13. After winding the V-phase coil CV3, the coil wire CL is wound a predetermined number of times clockwise around the outer circumference of the tenth tooth 4J from one end in the axial direction of the stator core 2 . As a result, the V-phase coil CV4 is wound around the outer circumference of the tenth tooth 4J by concentrated winding.

After winding the V-phase coil CV4, the coil wire CL is wound a predetermined number of times in the counterclockwise direction from one axial end of the stator core 2 to the outer periphery of the third tooth 4C. As a result, the V-phase coil CV1 is wound around the outer periphery of the third tooth 4C by concentrated winding. Before winding the coil wire CL around the outer periphery of the third teeth 4C, (part of) the crossover portion CL ₆ of the coil wire CL connecting the V-phase coils CV4 and CV1 is wound around the connection terminal 6a of the V-phase bus bar 6 held by the holding portion 13. After winding the V-phase coil CV1, the coil wire CL is wound a predetermined number of times clockwise from one axial end of the stator core 2 around the outer circumference of the fourth tooth 4D. As a result, the V-phase coil CV2 is wound around the outer periphery of the fourth tooth 4D by concentrated winding.

After winding the V-phase coil CV2 (four V-phase coils CV1 to CV4 in total), the coil wire CL is wound from one axial end of the stator core 2 around the outer periphery of the fifth tooth 4E in the counterclockwise direction for a predetermined number of times. As a result, the W-phase coil CW1 is wound around the outer periphery of the fifth tooth 4E by concentrated winding. Before winding the coil wire CL around the outer circumference of the fifth tooth 4E, (part of) the crossover portion CL ₈ of the coil wire CL connecting the V-phase coil CV2 and the W-phase coil CW1 is wound around the connection terminal 8b of the neutral point bus bar 8 held by the holding portion 13. After winding the W-phase coil CW1, the coil wire CL is wound a predetermined number of times clockwise from one axial end of the stator core 2 to the outer periphery of the sixth tooth 4F. As a result, the W-phase coil CW2 is wound around the outer periphery of the sixth tooth 4F by concentrated winding.

After winding the W-phase coil CW2, the coil wire CL is wound a predetermined number of times in the counterclockwise direction from one end of the stator core 2 in the axial direction around the outer periphery of the eleventh tooth 4K. As a result, the W-phase coil CW3 is wound around the outer circumference of the eleventh tooth 4K by concentrated winding. Before winding the coil wire CL around the outer circumference of the eleventh tooth 4K, (part of) the crossover portion CL ₁₀ of the coil wire CL connecting the W-phase coils CW2 and CW3 is wound around the connection terminal 7a of the W-phase bus bar 7 held by the holding portion 13. After the W-phase coil CW3 is wound, the coil wire CL is wound a predetermined number of times clockwise around the outer periphery of the twelfth tooth 4L from one end in the axial direction of the stator core 2 . As a result, the W-phase coil CW4 is wound around the outer periphery of the twelfth tooth 4L by concentrated winding.

As described above, a total of four U-phase coils, a total of four V-phase coils, and a total of four W-phase coils are sequentially formed along the longitudinal direction of one continuous coil wire CL. A winding start portion CL _s and a winding end portion CL _f of a single continuous coil wire CL in which a total of 12 coils C are formed are both wrapped around the connection terminal 8 c of the neutral point bus bar 8 . As a result, the coil winding process of winding the coil C on each of the total 12 teeth 4 by concentrated winding is completed.

[Connection process]
In this connection step, the coil wire CL (the connecting wire portion thereof) that is bound by the connection terminals of the bus bars 5 to 8 is connected to the connection terminal that is bound. in particular,
- The connecting wire portion _CL2 of the coil wire CL is connected to the connection terminal 5a of the U-phase bus bar 5,
The connecting wire portion _CL6 of the coil wire CL is connected to the connection terminal 6a of the V-phase bus bar 6,
The connecting wire portion CL ₁₀ of the coil wire CL is connected to the connection terminal 7a of the W-phase bus bar 7,
- The connecting wire portion _CL4 of the coil wire CL is connected to the connection terminal 8a of the neutral point bus bar 8,
The connecting wire portion CL ₈ of the coil wire CL is connected to the connection terminal 8b of the neutral point bus bar 8,
The connecting wire portion CL ₁₂ of the coil wire CL (the start line CL _s and finish line CL _f of the coil wire CL) is connected to the connection terminal 8 c of the neutral point bus bar 8 .

Although illustration is omitted, the connection of the coil wire CL is performed by so-called fusing (thermal crimping) in which a pair of electrodes compresses the coil wire CL, which is entwined with the connection terminals of the busbar, in the direction of the wire diameter and energizes the pair of electrodes for a predetermined period of time. In the case of fusing, the conductor wire can be joined to the connection terminal at substantially the same time as the insulation film of the coil wire CL made of the conductor wire with the insulation film is removed, so that the coil wire CL can be connected efficiently.

The connection of the coil wire CL (the connecting wire portion thereof) to the six connection terminals may be performed individually or collectively. In addition, prior to performing the coil winding process described above, the insulating coating may be removed from the portion of the coil wire CL that is bound around the connection terminal (the region to be bonded to the terminal). In this case, in the connection step, for example, the coil wire CL can be connected to the connection terminal only by crimping the portion of the coil wire CL that is wrapped around the connection terminal (the portion where the insulation film is removed), and the coil wire CL can also be connected to the connection terminal by welding such as TIG welding or laser welding.

When the coil wire CL is connected to the connection terminals of the bus bars 5-8 in the above manner, as shown in FIG. 5, a U-phase coil section 21 in which a total of four U-phase coils CU1-CU4 are connected in 2-parallel and 2-series, a V-phase coil section 22 in which a total of 4 V-phase coils CV1-CV4 are connected in 2-parallel and 2-series, and a total of 4 W-phase coils CW1-CW4 are connected in 2-parallel and 2-series. A motor drive circuit 20 is obtained in which the W-phase coil portion 23 is connected to each other (star connection) using the bus bars 5-8.

In the U-phase coil section 21 of the present embodiment, a first row formed by connecting the U-phase coils CU1 and CU2 in series and a second row formed by connecting the U-phase coils CU3 and CU4 in series are connected in parallel by a connecting wire portion CL ₂ of the coil wire CL that connects the U-phase coils CU2 and CU3. In the V-phase coil section 22, a first row formed by connecting the V-phase coils CV3 and CV4 in series and a second row formed by connecting the V-phase coils CV1 and CV2 in series are connected in parallel by a connecting wire portion CL ₆ of the coil wire CL that connects the V-phase coils CV4 and CV1. In the W-phase coil section 23, a first row formed by connecting the W-phase coils CW1 and CW2 in series and a second row formed by connecting the W-phase coils CW3 and CW4 in series are connected in parallel by a connecting wire portion CL ₁₀ of the coil wire CL that connects the W-phase coils CW2 and CW3.

As described above, in the motor stator 1 of this embodiment,
By sequentially winding one continuous coil wire CL around each of a total of 12 teeth 4 by concentrated winding, a total of four U-phase coils CU1 to CU4, a total of four V-phase coils CV1 to CV4 (in the order of CV3 → CV4 → CV1 → CV2), and a total of four W-phase coils CW1 to CW4 are formed in order along the longitudinal direction of the coil wire CL,
Of the coil wire CL, a connecting wire portion CL ₂ that connects the U-phase coils CU2 and CU3 in parallel, a connecting wire portion CL 6 that connects the V-phase coils CV4 and CV1 in parallel _{, and a connecting wire portion CL 10} _that connects the W-phase coils CW2 and CW3 in parallel are connected to the connecting terminal 5a of the U-phase bus bar 5, the connecting terminal 6a of the V-phase bus bar 6, and the connecting terminal 7a of the W-phase bus bar 7, respectively. Along with connecting
Of the coil wire CL, a crossover portion CL4 that connects the U-phase coil CU4 and the V-phase coil CV3 (the U-phase coil portion 21 and the V-phase coil portion 22), a crossover portion CL8 that connects the V-phase coil CV2 and the W-phase coil CW1 (the V-phase coil portion 22 and the W-phase coil portion 23), and a crossover portion CL12 that connects the W-phase coil CW4 and the U-phase coil CU1 (the W-phase coil portion 23 and the U-phase coil portion 21). are respectively connected to the connection terminals 8a to 8c of the neutral point bus bar 8, a star-connected motor drive circuit 20 is formed.

For example, when forming a drive circuit (star connection) for a three-phase brushless motor with 10 poles and 12 slots, there are a maximum of 12 connection points for a total of 4 busbars (U-phase busbar, V-phase busbar, W-phase busbar, and neutral point busbar). On the other hand, if the motor drive circuit 20 is formed in the manner described above, the number of connection points for the four bus bars 5 to 8 can be reduced to six. As a result, the cost of the motor stator 1 can be reduced through the simplification of the wire connection work.

In addition, in the motor stator 1 of the present embodiment, a total of four busbars 5 to 8 are held by (the holding portion 13 of) the insulating member 10 on one axial end side of the stator core 2 in a non-contact state. This means that the insulating member 10 for insulating between the teeth 4 and the coil C wound thereon integrally has a portion corresponding to the busbar holder of the conventional busbar unit. In this case, the number of parts can be reduced because the bus bar unit, which is generally provided separately from the motor stator, is not required. Further, in this case, when the coil C is wound, the planned connection points (connection wire portions) of the coil wire CL to the busbars 5 to 8 can be brought into contact with the connection terminals of the busbars 5 to 8 (in this embodiment, they are bound), so that the connection work after the coil winding can be performed easily and accurately. Therefore, the cost of the stator core 1 can be reduced by reducing the number of parts and facilitating the connection work.

Although the motor stator 1 according to the embodiment of the present invention has been described above, the motor stator 1 can be appropriately modified as long as the gist of the present invention is not changed. For example, the winding order of the coils C when one continuous coil wire CL is sequentially wound around each of a total of 12 teeth 4 by concentrated winding can be changed as shown in FIG. Specifically, after winding the U-phase coil CU4 around the eighth tooth 4H, and before winding the W-phase coil CW1 around the fifth tooth 4E, the V-phase coil may be wound in the order of CV4→CV3→CV2→CV1. However, in this case, among the coil wires CL, the connecting wire portions that connect two coils that are adjacent in the longitudinal direction include those in which the winding direction in the circumferential direction of the stator core 2 is in the positive direction and those in which the winding direction is in the opposite direction.

On the other hand, in the above-described embodiment, the winding directions in the circumferential direction of the connecting wire portions (CL ₁ to CL ₁₂ ) are all the same (when the coils are wound in the order shown in FIG. 4 on each of the teeth 4 arranged in the manner shown in FIG. 3, the winding directions of the connecting wire portions are all counterclockwise). In this case, since the coil wire CL is not folded back when the coil is successively wound around each tooth 4 by concentrated winding, it is possible to prevent the motor stator 1 from becoming larger and the coil wire CL from breaking due to stacking of the crossover portions in the axial direction. Conversely, when the coil C is wound in the order shown in FIG. 6, if the crossover wire portion with the positive winding direction in the circumferential direction and the crossover wire portion with the opposite winding direction in the circumferential direction coexist, the motor stator 1 may be enlarged in the axial direction, or the coil wire CL may be broken. Therefore, it is preferable that all of the connecting wire portions (CL ₁ to CL ₁₂ ) have the same winding direction in the circumferential direction.

Although the case where the present invention is applied to the stator 1 for a 10-pole, 12-slot three-phase brushless motor (fractional groove motor) has been described above, the present invention can also be applied to stators for other fractional-groove motors, such as stators for 14-pole, 12-slot, three-phase brushless motors, and stators for 14-pole, 18-slot, three-phase brushless motors. In the latter case, for example, a motor drive circuit is formed by star-connecting U-phase to W-phase coils connected in two parallel and three series.

The present invention is by no means limited to the embodiments described above, and it goes without saying that it can be embodied in various forms without departing from the gist of the present invention. The scope of the present invention is indicated by the claims, and includes equivalent meanings and all changes within the scope of the claims.

Reference Signs List 1 motor stator 2 stator core 4 teeth 5 U-phase busbar 5a connection terminal 6 V-phase busbar 6a connection terminal 7 W-phase busbar 7a connection terminal 8

neutral point busbars

8a, 8b, 8c connection terminal 10 insulating member 13 holding portion 20 motor drive circuit 30 motor 32 motor rotor 33 output shaft 35 Permanent magnet C Coil CU1, CU2, CU3, CU4 U-phase coil CV1, CV2, CV3, CV4 V-phase coil CW1, CW2, CW3, CW4 W-phase coil CL Coil wire CL ₁ to CL ₁₂ connecting wire

Claims

A motor stator comprising a cylindrical stator core having a plurality of teeth spaced apart in a circumferential direction, and a plurality of U-phase coils, V-phase coils and W-phase coils formed by winding a coil wire around each of the plurality of teeth via an insulating member,
The plurality of U-phase coils, the plurality of V-phase coils, and the plurality of W-phase coils are sequentially formed along the longitudinal direction of the coil wire by sequentially winding one continuous coil wire around each of the plurality of teeth by concentrated winding,
Among the coil wires, a crossover wire portion that connects the U-phase coils in parallel, a crossover wire portion that connects the V-phase coils in parallel, and a crossover wire portion that connects the W-phase coils in parallel are respectively connected to a connection terminal of the U-phase bus bar, a connection terminal of the V-phase bus bar, and a connection terminal of the W-phase bus bar. A motor stator, wherein a star-connected motor drive circuit is formed by connecting a connecting wire portion connecting said W-phase coil and said U-phase coil to a connection terminal of a neutral point bus bar.
The motor stator according to claim 1, wherein the U-phase bus bar, the V-phase bus bar, the W-phase bus bar, and the neutral point bus bar are held in non-contact with the insulating member on one axial end side of the stator core.
The motor stator according to claim 2, wherein the U-phase busbar, the V-phase busbar, the W-phase busbar and the neutral point busbar are outserted into grooves provided in the insulating member.
The motor stator according to any one of claims 1 to 3, wherein each connecting wire portion is connected to a corresponding connection terminal by fusing.
The motor stator according to any one of claims 1 to 4, wherein the winding directions in the circumferential direction of each connecting wire portion are all the same.
The motor stator according to any one of claims 1 to 5, wherein the parallel number of the U-phase coils, the parallel number of the V-phase coils, and the parallel number of the W-phase coils are all even numbers.
The motor stator according to any one of claims 1 to 6, which is for a three-phase brushless motor with 10 poles and 12 slots.
A motor comprising the motor stator according to any one of claims 1 to 7 and a motor rotor.